1. Field of the Invention
The present invention relates to a mobile communication system, and particularly, to an apparatus and a method for controlling a receiving rate of a global positioning system (GPS) signal in order to improve the receiving rate of the GPS signal.
2. Background of the Related Art
FIG. 1 shows a conventional GPS signal receiver. As shown therein, the conventional GPS signal receiver comprises a down converter 10 for converting a global positioning system (GPS) satellite signal (referred to as GPS signal) which is received through an antenna (ANT) into an intermediate frequency (IF) signal; a GPS signal processing unit 20 converting the IF signal into a digital signal and processing the signal by channels (the number of GPS satellites) to output GPS data including time and position data and status information representing normal/abnormal status of the GPS data; a micro processor unit (MPU) 30 for transmitting the GPS data and the status information inputted from the GPS signal processing unit 20 to a clock signal generator 40; a clock signal generator 40 for performing position and time control using the GPS data according to the status data outputted from the MPU 30 and a memory 50.
The GPS signal processing unit 20 comprises an analog/digital converter 1 for converting the IF signal outputted from the down converter 10 into the digital signal; and a data detecting unit 2 for processing the digital IF signal outputted from the analog/digital converter 1 and for outputting the GPS data and the status information.
Operations of the conventional GPS data receiver constructed as above will be described as follows with reference to FIG. 1.
When the GPS signal is received from the GPS satellite, the down converter 10 converts the GPS signal into the IF signal to output the signal to the GPS signal processing unit 20.
The analog/digital converter 1 of the GPS signal processing unit 20 converts the inputted IF signal into the digital IF signal, and the data detecting unit 2 processes the digital IF signal by channels to output the status information representing the normal/abnormal status of the GPS data. That is, the GPS signal processing unit 20 checks the GPS data, and outputs the status information indicating an abnormal status to the MPU 30 when the position and/or time data is abnormal. At that time, the GPS data and the status information outputted from the GPS signal processing unit 20 are temporarily stored in the memory 50.
The MPU 30 outputs the GPS data and the status information outputted from the GPS signal processing unit 20 to the clock signal generator 40, and the clock signal generator 40 checks the inputted status information. The clock signal generator 40 then performs time and position controls using the GPS data. At that time, the clock signal generator 40 masks the position and time data if the status information indicates an abnormal status, and performs position and time control of the mobile terminal using the position and time data if the status information indicates a normal status.
Generally, in an urban area having bad GPS reception, the status information is likely to indicate an abnormal status since the position information is not good. However, once an abnormal status is detected, the clock generator 40 discards all GPS data of the corresponding GPS satellite, that is, discards good time data as well as the inferior position data.
Therefore, according to the conventional GPS receiver, the good time data as well as the inferior position data is discarded when the status information indicates an abnormal status, and therefore, the entire GPS signal receiving rate (usage rate) is lowered and a system error may be caused.
An object of the invention is to solve at least the above problems and/or disadvantages and to provide at least the advantages described hereinafter.
One embodiment of the present invention provides an apparatus and a method for controlling a receiving rate of a GPS signal to improve the receiving rate.
Another embodiment of the present invention provides an apparatus and a method for controlling a receiving rate of a GPS signal that minimizes system error by improving the receiving rate of the GPS signal.
One embodiment of the present invention includes an apparatus for controlling a receiving rate of the GPS signal comprising: a GPS signal processing unit for detecting GPS data and status information from a GPS satellite signal; a receiving rate controlling unit for forcedly outputting normal status information and GPS data that was outputted previously when the status information detected in the GPS signal processing unit indicates an abnormal status (abnormal status information) and a clock signal generator for performing position/time control of a mobile terminal according to the GPS data and the status information outputted from the receiving rate controlling unit.
Another embodiment of the present invention includes an apparatus for controlling a receiving rate of a GPS signal comprising: a GPS signal processing unit for outputting GPS data and status information by processing a GPS satellite signal; a status detecting unit checking the status information to output the GPS data and the status information outputted from the GPS signal processing unit when the status information indicates a normal status (normal status information) and to output a driving signal for a predetermined time and output GPS data stored in a memory simultaneously when the status information indicates an abnormal status; a normal status generator for generating status information indicating a normal status according to the driving signal; and a counter for counting according to the driving signal to output a time-out signal to the status detecting unit.
Another embodiment of the present invention includes a method for controlling a receiving rate of a GPS signal comprising: detecting GPS data and status information from a GPS satellite signal; checking a status of the detected status information; outputting GPS data and the status information without change when the detected status information indicates a normal status, or forcedly outputting status information indicating a normal status and previous GPS data for a predetermined time when the status data indicates an abnormal status; and performing position/time control of a mobile terminal according to the outputted GPS data and normal status data.
The foregoing and other features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims.